Blinds are widely used in various places. A blind is made up of several slats which are able to be gathered at a side of the window to reveal the view or be simply angled while allowing some light to travel through the blind yet retaining some level of privacy. These slats can be angled by pulling a draw cord. In detail, the draw cord is coiled on a spool which is connected to a worm rod, and the worm rod is engaged with a worm gear. When the spool is rotated by the draw cord, the spool can angle the slats through driving the worm gear and the worm rod. It is noted that the slats are only allowed to be pivoted between a fully closed position and a fully opened position, the fully closed position is when the slats are pivoted to fully cover the window, and the fully opened position is when the slats are angled to reveal the view of the window.